M365TEAMS-003: External meeting participant settings
- Platform
- Entra ID / M365
- Category
- Microsoft Teams Security
- Severity
- Medium
- Zero Trust pillar
- Applications & Workloads (weight 1)
- Golden fixtures
- 3
- Branch coverage
- Observed: fixtures prove the verdicts they exercise
- Provenance
- baseline
What it checks
External meeting participant settings control what capabilities external users have when joining Teams meetings hosted by your organization. Allowing external participants to have presenter roles, bypass the lobby, or share screens without restriction can lead to meeting hijacking, unauthorized content sharing, and sensitive information exposure. Restricting external participant capabilities reduces the risk of meeting disruption and data leakage.
Recommended value
External participants default to attendee role; lobby bypass disabled for external users; screen sharing restricted to organizer and presenters only
Remediation
Configure the global meeting policy to require external participants to wait in the lobby and default to the attendee role when admitted to meetings. Restrict screen sharing and content sharing to meeting organizers and designated presenters to prevent unauthorized content sharing by external attendees. Create specific meeting policies for different user groups if some departments require more permissive settings for regular external collaboration.
Fixture-proven verdicts
Every verdict below is proven by a golden fixture in the module's gating test suite. This table derives from the last green run; it cannot be edited by hand.
| Scenario | Expected verdict |
|---|---|
| clean | PASS |
| known-bad | FAIL |
| no-data | Not Assessed |
Framework mappings
- CISA SCuBA
- MS.TEAMS.1.1v1
- NIST SP 800-53
- AC-20
- CIS M365 Benchmark
- 8.5.1